Optical coupler for lidar sensor

ABSTRACT

A light detection and ranging (LIDAR) device includes a waveguide, cladding, and a scattering array. The waveguide is configured to route an infrared optical field. The cladding is disposed around the waveguide. The scattering array is formed in the cladding. The scattering array is configured to perturb the infrared optical field routed by the waveguide to direct the infrared optical field into an infrared beam propagating toward a surface of the cladding.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional Application No.63/117,316 filed Nov. 23, 2020, which is hereby incorporated byreference.

TECHNICAL FIELD

This disclosure relates generally to optics and in particular to lightdetection and ranging (LIDAR).

BACKGROUND INFORMATION

Frequency Modulated Continuous Wave (FMCW) LIDAR directly measures rangeand velocity of an object by directing a frequency modulated, collimatedlight beam at a target. Both range and velocity information of thetarget can be derived from FMCW LIDAR signals. Designs and techniques toincrease the accuracy of LIDAR signals are desirable.

The automobile industry is currently developing autonomous features forcontrolling vehicles under certain circumstances. According to SAEInternational standard J3016, there are 6 levels of autonomy rangingfrom Level 0 (no autonomy) up to Level 5 (vehicle capable of operationwithout operator input in all conditions). A vehicle with autonomousfeatures utilizes sensors to sense the environment that the vehiclenavigates through. Acquiring and processing data from the sensors allowsthe vehicle to navigate through its environment. Autonomous vehicles mayinclude one or more LIDAR devices for sensing its environment.Conventional LIDAR systems require mechanical moving parts to steer thelaser beam used for imaging the sensing environment. They are consideredbulky, costly and unreliable for many applications, such as automotiveand robotics.

BRIEF SUMMARY OF THE INVENTION

Implementations of the disclosure include a light detection and ranging(LIDAR) device including a waveguide, a cladding, and a scatteringlayer. The waveguide is configured to route an infrared optical field.The cladding is disposed around the waveguide. The scattering array isformed in the cladding. The scattering array is configured to perturbthe infrared optical field routed by the waveguide to direct theinfrared optical field into an infrared beam propagating toward asurface of the cladding.

In an implementation, the scattering array is spaced apart from thewaveguide by a particular spacing distance and the waveguide is disposedbetween the scattering array and the surface of the cladding.

In an implementation, the LIDAR device includes a substrate layerinterfacing with the cladding. The scattering array is disposed betweenthe waveguide and an interface of the substrate layer and the cladding.

In an implementation, the LIDAR device further includes a reflectorlayer formed in the cladding. The waveguide is disposed between thereflector layer and the scattering array. The reflector layer isconfigured to direct the infrared beam to exit through the substratelayer.

In an implementation, a thickness between the scattering array and theinterface and a spacing distance between the waveguide and thescattering array are configured to increase an intensity of the infraredbeam by destructively interfering down-scattered portions of theinfrared optical field.

In an implementation, the scattering array is also configured to couplea received infrared beam into the waveguide and the received infraredbeam is a reflection of the infrared beam by a target in an externalenvironment of the LIDAR device.

In an implementation, the cladding is transparent to the infraredoptical field.

In an implementation, the waveguide has a first refractive index that ishigher than a second refractive index of the cladding.

In an implementation, the waveguide is tapered and flares outward as thewaveguide approaches the scattering array. The scattering array mayprogressively flares outward.

In an implementation, a polarization orientation of the infrared beammatches a long direction of scatterers in the scattering array.

In an implementation, the LIDAR device further includes a secondwaveguide. A first taper of the waveguide extends into a second taper ofthe second waveguide. The scattering array is a two-dimensional couplerconfigured to scatter the infrared optical field in a first polarizationorientation and configured to scatter a second infrared optical field ina second polarization orientation. The second infrared optical field isrouted by the second waveguide.

In an implementation, the infrared optical field routed in the waveguidepropagates orthogonal to the second infrared optical field propagatingin the second waveguide.

In an implementation, the waveguide and the second waveguide are formedin a same layer.

In an implementation, the waveguide is silicon nitride.

Implementations of the disclosure include an autonomous vehicle controlsystem for an autonomous vehicle including a LIDAR device and one ormore processors. The LIDAR device includes a waveguide, a cladding, anda scattering layer. The waveguide is configured to route an infraredoptical field. The cladding is disposed around the waveguide. Thescattering array is formed in the cladding. The scattering array isconfigured to perturb the infrared optical field routed by the waveguideto direct the infrared optical field into an infrared transmit beam. Theone or more processors are configured to control the autonomous vehiclein response to an infrared returning beam that is a reflection of theinfrared transmit beam.

In an implementation, a polarization orientation of the infraredtransmit beam matches a long direction of scatterers in the scatteringarray.

In an implementation, the LIDAR device further includes secondwaveguide. The scattering array is a two-dimensional coupler configuredto scatter the infrared optical field in a first polarizationorientation and configured to scatter a second infrared optical field ina second polarization orientation. The second infrared optical field isrouted by the second waveguide.

In an implementation, the scattering array is spaced apart from thewaveguide by a particular spacing distance.

Implementations of the disclosure include an autonomous vehicleincluding a LIDAR sensor and one or more processors. The LIDAR deviceincludes a waveguide, a cladding, and a scattering layer. The waveguideis configured to route an infrared optical field. The cladding isdisposed around the waveguide. The scattering array is formed in thecladding. The scattering array is configured to perturb the infraredoptical field routed by the waveguide to direct the infrared opticalfield into an infrared transmit beam. The one or more processors areconfigured to control the autonomous vehicle in response to an infraredreturning beam that is a reflection of the infrared transmit beam.

In an implementation, a polarization orientation of the infraredtransmit beam matches a long direction of scatterers in the scatteringarray

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the invention aredescribed with reference to the following figures, wherein likereference numerals refer to like parts throughout the various viewsunless otherwise specified.

FIG. 1A illustrates a cross section of an optical coupler emitting alight beam in an upward direction, in accordance with implementations ofthe disclosure.

FIG. 1B illustrates a received beam propagating through a surface andbeing coupled into an optical mode propagating in a waveguide, inaccordance with implementations of the disclosure.

FIG. 2 illustrates a cross section of an optical coupler including areflector layer configured to direct light to exit the optical couplerthrough a substrate layer, in accordance with implementations of thedisclosure.

FIGS. 3A-3C illustrate layers of a three-dimensional perspective of asingle-polarization (1D) optical coupler which has an optional topmetallic reflector, in accordance with implementations of thedisclosure.

FIGS. 4A-4B illustrate layers of a three-dimensional perspective of adual-polarization (2D) optical coupler without an optional reflectorlayer, in accordance with implementations of the disclosure.

FIG. 5A illustrates an autonomous vehicle including an array of examplesensors, in accordance with implementations of the disclosure.

FIG. 5B illustrates a top view of an autonomous vehicle including anarray of example sensors, in accordance with implementations of thedisclosure.

FIG. 5C illustrates an example vehicle control system including sensors,a drivetrain, and a control system, in accordance with implementationsof the disclosure.

DETAILED DESCRIPTION

Implementations of LIDAR optical couplers are described herein. In thefollowing description, numerous specific details are set forth toprovide a thorough understanding of the implementations. One skilled inthe relevant art will recognize, however, that the techniques describedherein can be practiced without one or more of the specific details, orwith other methods, components, materials, etc. In other instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring certain aspects.

Reference throughout this specification to “one implementation” or “animplementation” means that a particular feature, structure, orcharacteristic described in connection with the implementation isincluded in at least one implementation of the present invention. Thus,the appearances of the phrases “in one implementation” or “in animplementation” in various places throughout this specification are notnecessarily all referring to the same implementation. Furthermore, theparticular features, structures, or characteristics may be combined inany suitable manner in one or more implementations.

Throughout this specification, several terms of art are used. Theseterms are to take on their ordinary meaning in the art from which theycome, unless specifically defined herein or the context of their usewould clearly suggest otherwise. For the purposes of this disclosure,the term “autonomous vehicle” includes vehicles with autonomous featuresat any level of autonomy of the SAE International standard J3016.

Solid-state LIDAR devices are an improvement over the mechanical movingparts of conventional LIDAR by reducing or eliminating mechanicallymoving parts required to steer the optical beam for LIDAR operation. Animportant component in solid-state LIDAR systems is the optical couplerwhich emits and/or receives light. Optical efficiency is an importantaspect of the optical coupler.

Frequency Modulated Continuous Wave (FMCW) LIDAR directly measure rangeand velocity of an object/target by directing a frequency modulated,collimated light beam at the object. The light that is reflected fromthe object/target is combined with a tapped version of the beam. Thefrequency of the resulting beat tone is proportional to the distance ofthe object from the LIDAR system once corrected for the doppler shiftthat requires a second measurement. The two measurements, which may ormay not be performed at the same time, provide both range and velocityinformation.

An important consideration in the design of solid-state FMCW LIDARsystems is power handling capabilities. Increased power handling enablesimproved Signal to Noise Ratio (SNR) and longer distance rangeperformance. Developing an integrated optical platform that is anefficient manipulation of light while retaining high power-handlingcapabilities is desirable for high performance FMCW LIDAR systems.

Implementations of the disclosure include a LIDAR device including awaveguide, cladding, and a scattering array to direct the infraredoptical field into an infrared beam exiting a surface of the cladding ora substrate (e.g. silicon substrate) that supports the waveguide andcladding. The LIDAR device may include a reflector layer configured todirect the infrared beam to exit through the substrate layer. Thescattering array may also be configured to couple a received infraredbeam into the waveguide where the received infrared beam is a reflectionof the infrared beam by a target in an external environment of the LIDARdevice. The scattering array may be quasi-periodic. In someimplementations, a second waveguide extends into the waveguide and thescattering array is a two-dimensional coupler configured to scatter theinfrared optical field in a first polarization orientation andconfigured to scatter a second infrared optical field (routed by thesecond waveguide) in a second polarization orientation that isorthogonal to the first polarization orientation. These and otherimplementations are described in more detail in connection with FIGS.1A-5C.

FIG. 1A illustrates a cross section of an optical coupler 150 emittinglight beam 107 in an upward direction, in accordance withimplementations of the disclosure. Optical coupler 150 includes awaveguide 102, cladding 120, a scattering array 104, and a substratelayer 130. Waveguide 102 may be a silicon nitride slab, in animplementation. Cladding 120 is an oxide, in an implementation. Cladding120 is silicon dioxide, in an implementation. Cladding 120 may betransparent to infrared light. Waveguide 102 may have a first refractiveindex that is higher than a second refractive index of cladding 120.Substrate layer 130 may be a silicon wafer substrate. In FIG. 1A,substrate layer 130 is illustrated as interfacing with cladding 120 atan interface 109. When cladding 120 is silicon dioxide and substratelayer 130 is silicon, interface 109 may be considered a silicon-glassinterface.

Scattering array 104 is spaced apart from waveguide 102 by a spacingdistance 105 of cladding 120, in FIG. 1A. Scattering array 104 may bequasi-periodic. Scattering array 104 may include silicon scatters thatmay be formed of silicon. FIG. 1A includes twelve scatterers forillustration purposes although more or fewer scatters may be utilized.Scattering array 104 is disposed between waveguide 102 and interface109, in the illustrated implementation of FIG. 1A.

In operation, an optical mode 101 propagates through waveguide 102.Optical mode 101 may be an infrared optical field having a narrowlinewidth. Optical mode 101 may be generated from laser light coupledinto waveguide 102. The tails 103 of optical mode 101 extends outsidewaveguide 102. Waveguide 102 is configured to route optical mode 101. Asoptical mode 101 propagates, the tails 103 interact with the scatteringarray of silicon scatterers 104 which causes light to scatter out of thewaveguide 102 (e.g. a silicon nitride slab). Although FIG. 1Aillustrates the scatterers 104 as a single thickness, width, andspacing, these scatterers can have varying thicknesses, widths, andspacings in order to shape the generated beam of light 107 to aparticular shape. Depending on the spacing distance 105 (which may be anoxide spacer thickness) along with the duty factor of the scatterers104, the strength of this scattering can be controlled. In animplementation, scattering array 104 is configured to perturb aninfrared optical field 101 that is routed by a silicon-nitride waveguide102 to direct infrared optical field 101 into an infrared beam 107propagating toward surface 121 of cladding 120.

Light is scattered in both the downward (e.g. down-scattered light 106)and upward (e.g. beam 107) directions. Light scattered downwardspropagates through spacing distance 105, scatterers 104, and oxidethickness 108, eventually partially reflecting off of a silicon-glassinterface 109 as light 110. Thicknesses of 102, 104, 105, and 108 may beconfigured to cause destructive interference to optical wavespropagating through interface 109, thereby increasing the optical powerwhich propagates in the upwards direction as beam 107. The net effect isan upwards-propagating beam of light 107 which contains the majority ofoptical power contained in optical mode 101. In an implementation,spacing distance 105 and thickness 108 in cladding 120 are configured toincrease an intensity of beam 107 by destructively interferingdown-scattered portions 106 of optical field 101. Since beam 107 exitsthrough surface 121 of cladding 120, optical structure 150 may beconsidered a vertical optical coupler that is surface-emitting ratherthan edge emitting. Surface-emitting optical couplers may beadvantageous for LIDAR systems and devices.

In addition to being a transmit optical coupler that transmits beam 107,optical structure 150 may also function as a receive optical couplerthat receives incident light and couples the light into waveguide 102.FIG. 1B illustrates received beam 157 propagating through surface 121and being coupled into optical mode 151 propagating in waveguide 102 inan opposite direction as optical mode 101. Therefore, scattering array104 (and spacing distance 105 and thickness 108) may also be configuredto couple a received beam 157 into waveguide 102. Received beam 157 maybe a received infrared beam that is a reflection of infrared beam 107reflecting of a target in an external environment of optical structure150 when optical structure 150 is included in a LIDAR device. Hence,optical mode 151 may be converted into a received electrical signal in aLIDAR context.

FIG. 2 illustrates a cross section of an optical coupler 250 including areflector layer 212 configured to direct light to exit optical coupler250 through substrate layer 130, in accordance with implementations ofthe disclosure. In this implementation, substrate layer 130 istransparent to infrared light. Reflector layer 212 may be a metallicreflector layer, such as copper. Reflector layer 212 may also be adiffractive structure configured to reflect the linewidth of beam 207.Reflector layer 212 is formed in cladding 120. Waveguide 202 is disposedbetween reflector layer 212 and scattering array 204. Scattering array204 may be quasi-periodic. In operation, optical mode 201 propagatesthrough waveguide 202. Optical mode 201 may include the characteristicsassociated with optical mode 101. Waveguide 202 may have the featuresassociated with waveguide 102, in some implementations. Tails 203 ofoptical mode 201 extend outside of the waveguide material. Tails 203interact with scattering array of scatterers 204 which causes light toscatter out of the waveguide 202 as beam 207. Depending on the spacingdistance 205 in cladding 120, along with the duty factor of thescatterers 204, the strength of this scattering can be controlled anddesigned.

Light is scattered in both the downward (206) and upward (207)directions, in FIG. 2. Light scattered downwards propagates through thespacing distance 205, scatterers 204, and thickness 208, eventuallypartially reflecting off of an interface 109 as light 210. Light whichis scattered in the upwards direction as beam 207 passes through aspacing dimension 211 and encounters reflector layer 212 which reflectsa significant majority of the light downwards as beam 213. Bycontrolling the thicknesses of 202, 204, 205, 208, and 211, the opticalwaves which transmit through the interface 209 (including beam 213) canbe made to constructively interfere, forming a downward-propagating beamof light 214 which contains a significant majority of the power in theinput mode 201. Since beam 214 exits through the bottom side ofsubstrate layer 130, optical structure 250 may be considered a verticaloptical coupler that is surface-emitting rather than edge emitting.

FIGS. 3A-3C illustrate layers of a three-dimensional perspective of asingle-polarization (1D) optical coupler 350 which has an optional topmetallic reflector 312, in accordance with implementations of thedisclosure. Optical coupler 350 may be a hybrid silicon-silicon nitrideoptical coupler. FIG. 3A illustrates scattering array 304 disposed oversubstrate layer 130. Scattering array 304 may be quasi-periodic. FIGS.3A-3C do not specifically illustrate cladding 120 so as not to obscurethe other components of optical coupler 350. However, a thickness (e.g.thickness 108) of cladding 120 would support scattering array 304, forexample. Cladding 120 may also support waveguide 301 and reflector layer312.

FIG. 3B illustrates a waveguide 301 connecting to a tapered siliconnitride slab 302 which expands the input optical mode 101 to the desiredsize. Waveguide 301 is tapered and flares outward as the waveguideapproaches scattering array 304, in the illustrated implementation.Waveguide 301 and tapered nitride slab 302 may be a contiguous materialof silicon nitride. Waveguide 301 and slab 302 are disposed overscattering array 304 which control the scattering of light out of thesilicon nitride slab 302. The polarization state of emitted light (e.g.beam 214), and by extension, the polarization state of light which isefficiently received matches the long direction 391 of the scatterers ofscattering array 304. In an implementation, a polarization orientationof an infrared beam (generated by scattering array 304) matches a longdirection of the scatters of scattering array 304.

FIG. 3C illustrates optional reflector layer 312 disposed above slab302. Reflector layer 312 extends across an area comparable to or largerthan the area occupied by the scatterers of scattering array 304.Substrate layer 130 may act as an additional reflective interface whichcan be used to control the coupling of light into and out of the inputwaveguide 301. Other waveguide designs may be utilized in opticalcoupler 350 besides tapered slab depicted by 302. In an implementation,a straight non-tapered slab could be used to the same effect.Additionally, a transition between input waveguide 301 and slab 302 maybe adjusted.

FIGS. 4A-4B illustrate layers of a three-dimensional perspective of adual-polarization (2D) optical coupler 450 without an optional reflectorlayer, in accordance with implementations of the disclosure. Opticalcoupler 450 may be a hybrid silicon-silicon nitride optical coupler.FIG. 4A illustrates scattering array 404 disposed over substrate layer130. Scattering array 404 may be quasi-periodic. FIGS. 4A-4B do notspecifically illustrate cladding 120 so as not to obscure the othercomponents of optical coupler 450. However, a thickness (e.g. thickness108) of cladding 120 would support scattering array 404, for example.Cladding 120 may also support waveguide 401 and 402.

FIG. 4B illustrates a two-input waveguide 401 and 402 connecting to slab403 which expands the optical mode from either input waveguide 401 or402 to the desired size. Waveguide 401 receives optical mode 481 andwaveguide 402 receives optical mode 482. Slab 403 can be likened to two1D coupler slabs 302 (FIG. 3B) rotated by 90 degrees and merged, in someimplementations. A first taper of waveguide 401 extends into a secondtaper of waveguide 402, in an implementation. Depending on whether lightenters from waveguide 401 or 402, light is scattered in one of twoorthogonal polarization states by scattering array 404. Optical mode 481will be scattered by scattering array 404 in a first polarizationorientation and optical mode 482 will be scattered by scattering array404 in a second polarization orientation that is orthogonal to the firstpolarization orientation, in some implementations.

In the illustration of FIG. 4B, optical field 481 routed by waveguide401 propagates orthogonal to optical field 482 propagating in thewaveguide 402. A polarization state of incident light (e.g. a reflectionof a transmit beam emitted by optical coupler 450) on optical coupler450 may influence which waveguide the light is routed into. In someimplementations, scattering array 404 is configured to direct a firstpolarization orientation of incident light to waveguide 401 andconfigured to direct a second polarization orientation of the incidentlight to waveguide 402. Thus, in a dual-polarization configuration,optical couplers of this disclosure may transmit and receive light intwo orthogonal polarization states.

Optical structures 150, 250, 350, and 450 may be considered integratedvertical optical couplers since they may transmit and/or receive lightthrough a top or bottom surface of a cladding layer or substrate layer.In other words, optical structures 150, 250, 350, and 450 may be surfaceemitting rather than edge-emitting. These vertically propagating beamsof light may be projected onto the environment to perform a LiDARmeasurement.

FIG. 5A illustrates an example autonomous vehicle 500 that may includethe optical structures of FIGS. 1A-4B in a LIDAR device, in accordancewith aspects of the disclosure. The illustrated autonomous vehicle 500includes an array of sensors configured to capture one or more objectsof an external environment of the autonomous vehicle and to generatesensor data related to the captured one or more objects for purposes ofcontrolling the operation of autonomous vehicle 500. FIG. 5A showssensor 533A, 533B, 533C, 533D, and 533E. FIG. 5B illustrates a top viewof autonomous vehicle 500 including sensors 533F, 533G, 533H, and 533Iin addition to sensors 533A, 533B, 533C, 533D, and 533E. Any of sensors533A, 533B, 533C, 533D, 533E, 533F, 533G, 533H, and/or 533I may includeLIDAR devices that include the designs of FIGS. 1A-4B. FIG. 5Cillustrates a block diagram of an example system 599 for autonomousvehicle 500. For example, autonomous vehicle 500 may include powertrain502 including prime mover 504 powered by energy source 506 and capableof providing power to drivetrain 508. Autonomous vehicle 500 may furtherinclude control system 510 that includes direction control 512,powertrain control 514, and brake control 516. Autonomous vehicle 500may be implemented as any number of different vehicles, includingvehicles capable of transporting people and/or cargo and capable oftraveling in a variety of different environments. It will be appreciatedthat the aforementioned components 502-516 can vary widely based uponthe type of vehicle within which these components are utilized.

The implementations discussed hereinafter, for example, will focus on awheeled land vehicle such as a car, van, truck, or bus. In suchimplementations, prime mover 504 may include one or more electric motorsand/or an internal combustion engine (among others). The energy sourcemay include, for example, a fuel system (e.g., providing gasoline,diesel, hydrogen), a battery system, solar panels or other renewableenergy source, and/or a fuel cell system. Drivetrain 508 may includewheels and/or tires along with a transmission and/or any othermechanical drive components suitable for converting the output of primemover 504 into vehicular motion, as well as one or more brakesconfigured to controllably stop or slow the autonomous vehicle 500 anddirection or steering components suitable for controlling the trajectoryof the autonomous vehicle 500 (e.g., a rack and pinion steering linkageenabling one or more wheels of autonomous vehicle 500 to pivot about agenerally vertical axis to vary an angle of the rotational planes of thewheels relative to the longitudinal axis of the vehicle). In someimplementations, combinations of powertrains and energy sources may beused (e.g., in the case of electric/gas hybrid vehicles). In someimplementations, multiple electric motors (e.g., dedicated to individualwheels or axles) may be used as a prime mover.

Direction control 512 may include one or more actuators and/or sensorsfor controlling and receiving feedback from the direction or steeringcomponents to enable the autonomous vehicle 500 to follow a desiredtrajectory. Powertrain control 514 may be configured to control theoutput of powertrain 502, e.g., to control the output power of primemover 504, to control a gear of a transmission in drivetrain 508,thereby controlling a speed and/or direction of the autonomous vehicle500. Brake control 516 may be configured to control one or more brakesthat slow or stop autonomous vehicle 500, e.g., disk or drum brakescoupled to the wheels of the vehicle.

Other vehicle types, including but not limited to off-road vehicles,all-terrain or tracked vehicles, or construction equipment willnecessarily utilize different powertrains, drivetrains, energy sources,direction controls, powertrain controls, and brake controls, as will beappreciated by those of ordinary skill having the benefit of the instantdisclosure. Moreover, in some implementations some of the components canbe combined, e.g., where directional control of a vehicle is primarilyhandled by varying an output of one or more prime movers. Therefore,implementations disclosed herein are not limited to the particularapplication of the herein-described techniques in an autonomous wheeledland vehicle.

In the illustrated implementation, autonomous control over autonomousvehicle 500 is implemented in vehicle control system 520, which mayinclude one or more processors in processing logic 522 and one or morememories 524, with processing logic 522 configured to execute programcode (e.g. instructions 526) stored in memory 524. Processing logic 522may include graphics processing unit(s) (GPUs) and/or central processingunit(s) (CPUs), for example. Vehicle control system 520 may beconfigured to control powertrain 502 of autonomous vehicle 500 inresponse to infrared returning beams that are a reflection of aninfrared transmit beam emitted by optical structures 150, 250, 350,and/or 450 into an external environment of autonomous vehicle 500 andreflected back to optical structures 150, 250, 350, and/or 450.

Sensors 533A-533I may include various sensors suitable for collectingdata from an autonomous vehicle's surrounding environment for use incontrolling the operation of the autonomous vehicle. For example,sensors 533A-533I can include RADAR unit 534, LIDAR unit 536, 3Dpositioning sensor(s) 538, e.g., a satellite navigation system such asGPS, GLONASS, BeiDou, Galileo, or Compass. The optical coupler designsof FIGS. 1A-4B may be included in LIDAR unit 536. LIDAR unit 536 mayinclude a plurality of LIDAR sensors that are distributed aroundautonomous vehicle 500, for example. In some implementations, 3Dpositioning sensor(s) 538 can determine the location of the vehicle onthe Earth using satellite signals. Sensors 533A-533I can optionallyinclude one or more ultrasonic sensors, one or more cameras 540, and/oran Inertial Measurement Unit (IMU) 542. In some implementations, camera540 can be a monographic or stereographic camera and can record stilland/or video images. Camera 540 may include a ComplementaryMetal-Oxide-Semiconductor (CMOS) image sensor configured to captureimages of one or more objects in an external environment of autonomousvehicle 500. IMU 542 can include multiple gyroscopes and accelerometerscapable of detecting linear and rotational motion of autonomous vehicle500 in three directions. One or more encoders (not illustrated) such aswheel encoders may be used to monitor the rotation of one or more wheelsof autonomous vehicle 500.

The outputs of sensors 533A-533I may be provided to control subsystems550, including, localization subsystem 552, trajectory subsystem 556,perception subsystem 554, and control system interface 558. Localizationsubsystem 552 is configured to determine the location and orientation(also sometimes referred to as the “pose”) of autonomous vehicle 500within its surrounding environment, and generally within a particulargeographic area. The location of an autonomous vehicle can be comparedwith the location of an additional vehicle in the same environment aspart of generating labeled autonomous vehicle data. Perception subsystem554 may be configured to detect, track, classify, and/or determineobjects within the environment surrounding autonomous vehicle 500.Trajectory subsystem 556 is configured to generate a trajectory forautonomous vehicle 500 over a particular timeframe given a desireddestination as well as the static and moving objects within theenvironment. A machine learning model in accordance with severalimplementations can be utilized in generating a vehicle trajectory.Control system interface 558 is configured to communicate with controlsystem 510 in order to implement the trajectory of the autonomousvehicle 500. In some implementations, a machine learning model can beutilized to control an autonomous vehicle to implement the plannedtrajectory.

It will be appreciated that the collection of components illustrated inFIG. 5C for vehicle control system 520 is merely exemplary in nature.Individual sensors may be omitted in some implementations. In someimplementations, different types of sensors illustrated in FIG. 5C maybe used for redundancy and/or for covering different regions in anenvironment surrounding an autonomous vehicle. In some implementations,different types and/or combinations of control subsystems may be used.Further, while subsystems 552-558 are illustrated as being separate fromprocessing logic 522 and memory 524, it will be appreciated that in someimplementations, some or all of the functionality of subsystems 552-558may be implemented with program code such as instructions 526 residentin memory 524 and executed by processing logic 522, and that thesesubsystems 552-558 may in some instances be implemented using the sameprocessor(s) and/or memory. Subsystems in some implementations may beimplemented at least in part using various dedicated circuit logic,various processors, various field programmable gate arrays (“FPGA”),various application-specific integrated circuits (“ASIC”), various realtime controllers, and the like, as noted above, multiple subsystems mayutilize circuitry, processors, sensors, and/or other components.Further, the various components in vehicle control system 520 may benetworked in various manners.

In some implementations, different architectures, including variouscombinations of software, hardware, circuit logic, sensors, and networksmay be used to implement the various components illustrated in FIG. 5C.Each processor may be implemented, for example, as a microprocessor andeach memory may represent the random access memory (“RAM”) devicescomprising a main storage, as well as any supplemental levels of memory,e.g., cache memories, non-volatile or backup memories (e.g.,programmable or flash memories), or read-only memories. In addition,each memory may be considered to include memory storage physicallylocated elsewhere in autonomous vehicle 500, e.g., any cache memory in aprocessor, as well as any storage capacity used as a virtual memory,e.g., as stored on a mass storage device or another computer controller.Processing logic 522 illustrated in FIG. 5C, or entirely separateprocessing logic, may be used to implement additional functionality inautonomous vehicle 500 outside of the purposes of autonomous control,e.g., to control entertainment systems, to operate doors, lights, orconvenience features.

In addition, for additional storage, autonomous vehicle 500 may alsoinclude one or more mass storage devices, e.g., a removable disk drive,a hard disk drive, a direct access storage device (“DASD”), an opticaldrive (e.g., a CD drive, a DVD drive), a solid state storage drive(“SSD”), network attached storage, a storage area network, and/or a tapedrive, among others. Furthermore, autonomous vehicle 500 may include auser interface 564 to enable autonomous vehicle 500 to receive a numberof inputs from a passenger and generate outputs for the passenger, e.g.,one or more displays, touchscreens, voice and/or gesture interfaces,buttons and other tactile controls. In some implementations, input fromthe passenger may be received through another computer or electronicdevice, e.g., through an app on a mobile device or through a webinterface.

In some implementations, autonomous vehicle 500 may include one or morenetwork interfaces, e.g., network interface 562, suitable forcommunicating with one or more networks 570 (e.g., a Local Area Network(“LAN”), a wide area network (“WAN”), a wireless network, and/or theInternet, among others) to permit the communication of information withother computers and electronic devices, including, for example, acentral service, such as a cloud service, from which autonomous vehicle500 receives environmental and other data for use in autonomous controlthereof. In some implementations, data collected by one or more sensors533A-533I can be uploaded to computing system 572 through network 570for additional processing. In such implementations, a time stamp can beassociated with each instance of vehicle data prior to uploading.

Processing logic 522 illustrated in FIG. 5C, as well as variousadditional controllers and subsystems disclosed herein, generallyoperates under the control of an operating system and executes orotherwise relies upon various computer software applications,components, programs, objects, modules, or data structures, as may bedescribed in greater detail below. Moreover, various applications,components, programs, objects, or modules may also execute on one ormore processors in another computer coupled to autonomous vehicle 500through network 570, e.g., in a distributed, cloud-based, orclient-server computing environment, whereby the processing required toimplement the functions of a computer program may be allocated tomultiple computers and/or services over a network.

Routines executed to implement the various implementations describedherein, whether implemented as part of an operating system or a specificapplication, component, program, object, module or sequence ofinstructions, or even a subset thereof, will be referred to herein as“program code.” Program code typically comprises one or moreinstructions that are resident at various times in various memory andstorage devices, and that, when read and executed by one or moreprocessors, perform the steps necessary to execute steps or elementsembodying the various aspects of the invention. Moreover, whileimplementations have and hereinafter may be described in the context offully functioning computers and systems, it will be appreciated that thevarious implementations described herein are capable of beingdistributed as a program product in a variety of forms, and thatimplementations can be implemented regardless of the particular type ofcomputer readable media used to actually carry out the distribution.Examples of computer readable media include tangible, non-transitorymedia such as volatile and non-volatile memory devices, floppy and otherremovable disks, solid state drives, hard disk drives, magnetic tape,and optical disks (e.g., CD-ROMs, DVDs) among others.

In addition, various program code described hereinafter may beidentified based upon the application within which it is implemented ina specific implementation. However, it should be appreciated that anyparticular program nomenclature that follows is used merely forconvenience, and thus the invention should not be limited to use solelyin any specific application identified and/or implied by suchnomenclature. Furthermore, given the typically endless number of mannersin which computer programs may be organized into routines, procedures,methods, modules, objects, and the like, as well as the various mannersin which program functionality may be allocated among various softwarelayers that are resident within a typical computer (e.g., operatingsystems, libraries, API's, applications, applets), it should beappreciated that the invention is not limited to the specificorganization and allocation of program functionality described herein.

Those skilled in the art, having the benefit of the present disclosure,will recognize that the exemplary environment illustrated in FIG. 5C isnot intended to limit implementations disclosed herein. Indeed, thoseskilled in the art will recognize that other alternative hardware and/orsoftware environments may be used without departing from the scope ofimplementations disclosed herein.

In implementations of this disclosure, visible light may be defined ashaving a wavelength range of approximately 380 nm-700 nm. Non-visiblelight may be defined as light having wavelengths that are outside thevisible light range, such as ultraviolet light and infrared light.Infrared light having a wavelength range of approximately 700 nm-1 mmincludes near-infrared light. In aspects of this disclosure,near-infrared light may be defined as having a wavelength range ofapproximately 700 nm-1.6 μm.

In aspects of this disclosure, the term “transparent” may be defined ashaving greater than 90% transmission of light. In some aspects, the term“transparent” may be defined as a material having greater than 90%transmission of visible light.

The term “processing logic” in this disclosure may include one or moreprocessors, microprocessors, multi-core processors, Application-specificintegrated circuits (ASIC), and/or Field Programmable Gate Arrays(FPGAs) to execute operations disclosed herein. In some embodiments,memories (not illustrated) are integrated into the processing logic tostore instructions to execute operations and/or store data. Processinglogic may also include analog or digital circuitry to perform theoperations in accordance with embodiments of the disclosure.

A “memory” or “memories” described in this disclosure may include one ormore volatile or non-volatile memory architectures. The “memory” or“memories” may be removable and non-removable media implemented in anymethod or technology for storage of information such ascomputer-readable instructions, data structures, program modules, orother data. Example memory technologies may include RAM, ROM, EEPROM,flash memory, CD-ROM, digital versatile disks (DVD), high-definitionmultimedia/data storage disks, or other optical storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices, or any other non-transmission medium that can be usedto store information for access by a computing device.

Networks may include any network or network system such as, but notlimited to, the following: a peer-to-peer network; a Local Area Network(LAN); a Wide Area Network (WAN); a public network, such as theInternet; a private network; a cellular network; a wireless network; awired network; a wireless and wired combination network; and a satellitenetwork.

Communication channels may include or be routed through one or morewired or wireless communication utilizing IEEE 802.11 protocols,BlueTooth, SPI (Serial Peripheral Interface), I²C (Inter-IntegratedCircuit), USB (Universal Serial Port), CAN (Controller Area Network),cellular data protocols (e.g. 3G, 4G, LTE, 5G), optical communicationnetworks, Internet Service Providers (ISPs), a peer-to-peer network, aLocal Area Network (LAN), a Wide Area Network (WAN), a public network(e.g. “the Internet”), a private network, a satellite network, orotherwise.

A computing device may include a desktop computer, a laptop computer, atablet, a phablet, a smartphone, a feature phone, a server computer, orotherwise. A server computer may be located remotely in a data center orbe stored locally.

The processes explained above are described in terms of computersoftware and hardware. The techniques described may constitutemachine-executable instructions embodied within a tangible ornon-transitory machine (e.g., computer) readable storage medium, thatwhen executed by a machine will cause the machine to perform theoperations described. Additionally, the processes may be embodied withinhardware, such as an application specific integrated circuit (“ASIC”) orotherwise.

A tangible non-transitory machine-readable storage medium includes anymechanism that provides (i.e., stores) information in a form accessibleby a machine (e.g., a computer, network device, personal digitalassistant, manufacturing tool, any device with a set of one or moreprocessors, etc.). For example, a machine-readable storage mediumincludes recordable/non-recordable media (e.g., read only memory (ROM),random access memory (RAM), magnetic disk storage media, optical storagemedia, flash memory devices, etc.).

The above description of illustrated embodiments of the invention,including what is described in the Abstract, is not intended to beexhaustive or to limit the invention to the precise forms disclosed.While specific embodiments of, and examples for, the invention aredescribed herein for illustrative purposes, various modifications arepossible within the scope of the invention, as those skilled in therelevant art will recognize.

These modifications can be made to the invention in light of the abovedetailed description. The terms used in the following claims should notbe construed to limit the invention to the specific embodimentsdisclosed in the specification. Rather, the scope of the invention is tobe determined entirely by the following claims, which are to beconstrued in accordance with established doctrines of claiminterpretation.

What is claimed is:
 1. A light detection and ranging (LIDAR) devicecomprising: a waveguide configured to route an infrared optical field; acladding disposed around the waveguide; and a scattering array formed inthe cladding, wherein the scattering array is configured to perturb theinfrared optical field routed by the waveguide to direct the infraredoptical field into an infrared beam propagating toward a surface of thecladding.
 2. The LIDAR device of claim 1, wherein the scattering arrayis spaced apart from the waveguide by a particular spacing distance, andwherein the waveguide is disposed between the scattering array and thesurface of the cladding.
 3. The LIDAR device of claim 1 furthercomprising: a substrate layer interfacing with the cladding, wherein thescattering array is disposed between the waveguide and an interface ofthe substrate layer and the cladding.
 4. The LIDAR device of claim 3further comprising: a reflector layer formed in the cladding, whereinthe waveguide is disposed between the reflector layer and the scatteringarray, and wherein the reflector layer is configured to direct theinfrared beam to exit through the substrate layer.
 5. The LIDAR deviceof claim 3, wherein a thickness between the scattering array and theinterface and a spacing distance between the waveguide and thescattering array are configured to increase an intensity of the infraredbeam by destructively interfering down-scattered portions of theinfrared optical field.
 6. The LIDAR device of claim 1, wherein thescattering array is also configured to couple a received infrared beaminto the waveguide, wherein the received infrared beam is a reflectionof the infrared beam by a target in an external environment of the LIDARdevice.
 7. The LIDAR device of claim 1, wherein the cladding istransparent to the infrared optical field.
 8. The LIDAR device of claim1, wherein the waveguide has a first refractive index that is higherthan a second refractive index of the cladding.
 9. The LIDAR device ofclaim 1, wherein the waveguide is tapered and flares outward as thewaveguide approaches the scattering array, and wherein the scatteringarray progressively flares outward.
 10. The LIDAR device of claim 1,wherein a polarization orientation of the infrared beam matches a longdirection of scatterers in the scattering array.
 11. The LIDAR device ofclaim 1 further comprising: a second waveguide, wherein a first taper ofthe waveguide extends into a second taper of the second waveguide, andwherein the scattering array is a two-dimensional coupler configured toscatter the infrared optical field in a first polarization orientationand configured to scatter a second infrared optical field in a secondpolarization orientation, the second infrared optical field routed bythe second waveguide.
 12. The LIDAR device of claim 11, wherein theinfrared optical field routed in the waveguide propagates orthogonal tothe second infrared optical field propagating in the second waveguide.13. The LIDAR device of claim 11, wherein the waveguide and the secondwaveguide are formed in a same layer.
 14. The LIDAR device of claim 1,wherein the waveguide is silicon nitride.
 15. An autonomous vehiclecontrol system for an autonomous vehicle, the autonomous vehicle controlsystem comprising: a light detection and ranging (LIDAR) deviceincluding: a waveguide configured to route an infrared optical field; acladding disposed around the waveguide; and a scattering array formed inthe cladding, wherein the scattering array is configured to perturb theinfrared optical field routed by the waveguide to direct the infraredoptical field into an infrared transmit beam; and one or more processorsconfigured to control the autonomous vehicle in response to an infraredreturning beam that is a reflection of the infrared transmit beam. 16.The autonomous vehicle control system of claim 15, wherein apolarization orientation of the infrared transmit beam matches a longdirection of scatterers in the scattering array.
 17. The autonomousvehicle control system of claim 15, wherein the LIDAR device furtherincludes: a second waveguide, wherein the scattering array is atwo-dimensional coupler configured to scatter the infrared optical fieldin a first polarization orientation and configured to scatter a secondinfrared optical field in a second polarization orientation, the secondinfrared optical field routed by the second waveguide.
 18. Theautonomous vehicle control system of claim 15, wherein the scatteringarray is spaced apart from the waveguide by a particular spacingdistance.
 19. An autonomous vehicle comprising: a light detection andranging (LIDAR) sensor including: a waveguide configured to route aninfrared optical field; a cladding disposed around the waveguide; and ascattering array formed in the cladding, wherein the scattering array isconfigured to perturb the infrared optical field routed by the waveguideto direct the infrared optical field into an infrared transmit beam; andone or more processors configured to control the autonomous vehicle inresponse to an infrared returning beam that is a reflection of theinfrared transmit beam.
 20. The autonomous vehicle of claim 19, whereina polarization orientation of the infrared transmit beam matches a longdirection of scatterers in the scattering array.